Tanning animal hides



Patented Nov. 22, 1927.

PATENT FFIQ JOSEPH SCHZlFEB, OF HALTINGEN, GERMANY, ASSIGNOR TO THE FIRM J'. R. GEIGY TANNING ANIMAL HIDES.

No Drawing. Application filed September 1, 1926,

The salts of hydrofluosilicic acid have been found to have a distinct action on animal hides prepared for tanning, and to produce a weak tanning effect; with these agents alone, however, it is not possible to obtain a leather suitable for placing onthe market. By the present invention, the hides are treated with a salt of hydrofluosilicic acid, prior to, or simultaneously with, a vegetable, 1o mineral or synthetic tanning agent, such as, for example, a sulphite extract of quebracho, alum, a basic salt of chromium, iron or aluminium, tannin, or sulphite liquor, or with a mixture of such tanning agents.

When hides which have been treated with a salt of hydrofluosilicic acid, are tanned by means of the aforesaid tanning agents, the tanning agent is taken up extremely rapidly and easily, and in the correct quantity; '20 and an excellent and uniform tanning effect is produced; the tanning is more complete, and occupies a shorter time than isthe case in the usual tanning processes.

Another considerable advantage lies int-he fact that the treatment with a salt of hydrofiuosilicic acid produces a marked brightenlug effect in the tanned leather, som'e kiud of bleaching action occurring as a result of the treatment, I

A further advantage lies in the abundant absorption of the tanning agent which is Serial No. 133,087, and in Germany August 5, 1925.

shown by hides which have been pre-treated with a salt of hydrofiuosilicic acid.

Like results are attained if the treatment with a vegetable tanning agent, in about 3 hours, and calf-skins in about 6 hours, whilst if the pre-treatment is omitted, the remaining conditions being the same, a considerably longer time is necessary; for example, sheep-skins may require 2-3 days tanning, and calf-skins 2"4: days or more.

What I claim is p y 1. A process for tanning animal hides,

comprisingtreating the same with a salt of hydrofluosilicic acid. 2. A process for tanning animal hides, consisting in treating the same previously with a salt of hygrofluosilicic acid and sub jecting them thereupon to the tanning op- BlfiillOIl.

In Witness whereof I have hereunto signed my name this 19th day of August, 1926.

JOSEPH scI-IAFER, 

